312 OperationTires and wheelsMOExtended system*
The MOExtended system allows you to
continue driving your vehicle even if there
is a total loss of pressure in one or more
tires.
You may only use the MOExtended system
in conjunction with the Run Flat Indicator*.
!The maximum distance in emergency
mode depends on the vehicle’s load. It
is 30 miles (50 km) if the vehicle is par-
tially loaded and 18 miles (30 km) if the
vehicle is fully loaded.
The point at which the maximum driv-
ing distance begins in emergency
mode is when the warning message
appears in the multifunction display
indicating that there is a loss of tire
inflation pressure.
Do not exceed the maximum speed of
50 mph (80 km/h).
Warning!
G
In emergency mode, your vehicle’s driving
characteristics are diminished in such situa-
tions as:
driving around curves
while braking
while accelerating rapidly
Therefore, your driving style must be adapt-
ed accordingly. Avoid abrupt steering and
driving maneuvers, as well as driving over
obstacles (road curbs, potholes, or off-road
areas). This is especially important if the ve-
hicle is heavily loaded.
The emergency driving distance that can be
achieved greatly depends on the demands
placed on the vehicle. Depending on speed,
load, driving maneuvers, road conditions,
outside temperature, etc., the distance can
be significantly shorter or, if the vehicle is
driven cautiously, somewhat longer.
Do not continue driving in emergency mode
if
you notice knocking sounds
the vehicle starts to shake
smoke develops and you smell rubber
ESP is intervening continuously
you notice tears on the tire sidewalls
After driving in emergency mode, you must
have the rims inspected by an authorized
Mercedes-Benz Center to check if they are
suitable for further use. The failed tire must
be replaced in any case.iWhen replacing individual or all tires on
the vehicle, make sure only tires
marked with “MOExtended” are mount-
ed in the size specified for your vehicle
(page 413).
313 Operation
Tires and wheels
Tire labeling
Besides tire name (sales designation) and
manufacturer name, a number of markings
can be found on a tire.
Following are some explanations for the
markings on your vehicle’s tires:1Uniform Quality Grading Standards
(
page 320)
2DOT, Tire Identification Number (TIN)
(page 318)
3Maximum tire load (
page 319)
4Maximum tire inflation pressure
(
page 320)
5Manufacturer
6Tire ply material (
page 322)
7Tire size designation, load and speed
rating (
page 313)
8Load identification (
page 317)
9Tire nameTire size designation, load and speed
rating
1Tire width
2Aspect ratio in %
3Radial tire code
4Rim diameter
5Tire load rating
6Tire speed rating
iFor illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
For more information, see “Rims and
tires” (
page 413).
iFor illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
314 OperationTires and wheelsGeneral:
Depending on the design standards used,
the tire size molded into the sidewall may
have no letter or a letter preceding the tire
size designation.
No letter preceding the size designation
(as illustrated above): Passenger car tire
based on European design standards.
Letter “P” preceding the size designation:
Passenger car tire based on U.S. design
standards.
Letter “LT” preceding the size designation:
Light Truck tire based on U.S. design
standards.
Letter “T” preceding the size designation:
Temporary spare tires which are high
pressure compact spares designed for
temporary emergency use only. Tire width
The tire width1 (
page 313) indicates
the nominal tire width in mm.
Aspect ratio
The aspect ratio2 (page 313) is the
dimensional relationship between tire
section height and section width and is
expressed in percentage. The aspect ratio
is arrived at by dividing section height by
section width.
Tire code
The tire code3 (
page 313) indicates
the tire construction type. The “R” stands
for radial tire type. Letter “D” means diag-
onal or bias ply construction; letter “B”
means belted-bias ply construction.
At the tire manufacturer’s option, any tire
with a speed capability above 149 mph
(240 km/h) can include a “ZR” in the size
designation (for example: 245/40 ZR 18).
For additional information, see “Tire speed
rating” (
page 315).Rim diameter
The rim diameter4 (
page 313) is the
diameter of the bead seat, not the
diameter of the rim edge. Rim diameter is
indicated in inches (in).
Tire load rating
The tire load rating5 (page 313) is a
numerical code associated with the
maximum load a tire can support.
For example, a load rating of 91 corre-
sponds to a maximum load of 1 356 lbs
(615 kg) the tire is designed to support.
See also “Maximum tire load”
(
page 319) where the maximum load as-
sociated with the load index is indicated in
kilograms and lbs.
317 Operation
Tires and wheels
All-season and winter tires
Load identification
1Load identificationIn addition to tire load rating, special load
information may be molded into the tire
sidewall following the letter designating
the tire speed rating1 (
page 317).
No specification given: absence of any text
(like in above example) indicates a
standard load (SL) tire.
XL or Extra Load: designates an extra load
(or reinforced) tire.
Light Load: designates a light load tire.
C, D, E: designates load range associated
with the maximum load a tire can carry at
a specified pressure.
Index
Speed rating
QM+S
up to 100 mph (160 km/h)
TM+S
up to 118 mph (190 km/h)
HM+S
up to 130 mph (210 km/h)
VM+S
up to 149 mph (240 km/h)
iThe marking “M+S” next to the service
description designates tires with mud
and snow capabilities.
iFor illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
320 OperationTires and wheelsMaximum tire inflation pressure
1Maximum permissible tire inflation
pressure
This is the maximum permissible tire
inflation pressure for the tire.Always follow the recommended tire
inflation pressure (
page 306) for proper
tire inflation. Uniform Tire Quality Grading Standards
(U.S. vehicles)
Tire manufacturers are required to grade
tires based on three performance
factors: treadwear, traction and
temperature resistance.
1Treadwear
2Traction
3Temperature resistance
iFor illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
Warning!
G
Never exceed the max. tire inflation
pressure. Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and / or unevenly, adverse-
ly affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires
can adversely affect handling and ride com-
fort, wear unevenly, increase stopping dis-
tance, and result in sudden deflation
(blowout) because they are more likely to
become punctured or damaged by road de-
bris, potholes etc.
iFor illustration purposes only. Actual
data on tires is specific to each vehicle
and may vary from data shown in above
illustration.
323 Operation
Tires and wheels
Tire and loading terminology
Accessory weight
The combined weight (in excess of those
standard items which may be replaced) of
automatic transmission, power steering,
power brakes, power windows, power
seats, radio, and heater, to the extent that
these items are available as
factory-installed equipment (whether
installed or not).
Air pressure
The amount of air inside the tire pressing
outward on each square inch of the tire.
Air pressure is expressed in pounds per
square inch (psi), or kilopascal (kPa) or
bars.
Aspect ratio
Dimensional relationship between tire
section height and section width
expressed in percentage.Bar
Another metric unit for air pressure. There
are 14.5038 pounds per square inch (psi)
to 1 bar; there are 100 kilopascals (kPa)
to 1 bar.
Bead
The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the
rim.
Cold tire inflation pressure
Tire inflation pressure when your vehicle
has been sitting for at least three hours or
driven no more than one mile (1.6 km).
Curb weight
The weight of a motor vehicle with stan-
dard equipment including the maximum
capacity of fuel, oil, and coolant, and, if so
equipped, air conditioning and additional
optional equipment, but without passen-
gers and cargo.DOT (D
epartment o
f T
ransportation)
A tire branding symbol which denotes the
tire meets requirements of the
U.S. Department of Transportation.
GAWR (G
ross A
xle W
eight R
ating)
The GAWR is the maximum permissible
axle weight. The gross vehicle weight on
each axle must never exceed the GAWR for
the front and rear axle indicated on the
certification label located on the driver’s
door B-pillar.
GVW (G
ross V
ehicle W
eight)
The GVW comprises the weight of the
vehicle including fuel, tools, spare wheel,
installed accessories, passengers and
cargo and, if applicable, trailer tongue
load. The GWV must never exceed the
GWVR indicated on the certification label
located on the driver’s door B-pillar.
324 OperationTires and wheelsGVWR (G
ross V
ehicle W
eight R
ating)
This is the maximum permissible vehicle
weight of the fully loaded vehicle (weight of
the vehicle including all options, passen-
gers, fuel, and cargo and, if applicable,
trailer tongue load). It is indicated on
certification label located on the driver’s
door B-pillar.
Kilopascal (kPa)
The metric unit for air pressure. There are
6.9 kPa to one psi; another metric unit for
air pressure is bars. There are
100 kilopascals (kPa) to one bar.
Maximum load rating
The maximum load in kilograms and
pounds that can be carried by the tire.
Maximum loaded vehicle weight
The sum of curb weight, accessory weight,
vehicle capacity weight and production
options weight.Maximum tire inflation pressure
This number is the greatest amount of air
pressure that should ever be put in the tire
under normal driving conditions.
Normal occupant weight
The number of occupants the vehicle is
designed to seat, multiplied by
68 kilograms (150 lbs).
Occupant distribution
The distribution of occupants in a vehicle
at their designated seating positions.
Production options weight
The combined weight of those installed
regular production options weighing over
5 lbs (2.3 kilograms) in excess of those
standard items which they replace, not
previously considered in curb weight or
accessory weight, including heavy duty
brakes, ride levelers, roof rack, heavy duty
battery, and special trim.PSI (P
ounds per s
quare i
nch)
A standard unit of measure for air pressure
-> bar, kilopascal (kPa).
Recommended tire inflation pressure
Recommended tire inflation pressure
listed on placard located on driver’s door
B-pillar for normal driving conditions.
Provides best handling, tread life and
riding comfort.
Rim
A metal support for a tire or a tire and tube
assembly upon which the tire beads are
seated.
Sidewall
The portion of a tire between the tread and
the bead.
326 OperationTires and wheelsRotating tires
Tire rotation can be performed on vehicles
with tires of the same dimension all
around. If your vehicle is equipped with
tires of the same dimension all around,
tires can be rotated, observing a
front-to-rear rotation pattern that will
maintain the intended rotation (spinning)
direction of the tire (
page 300).
In some cases, such as when your vehicle
is equipped with mixed-size tires (different
tire dimension front vs. rear), tire rotation
is not possible.If applicable to your vehicle’s tire configu-
ration, tires can be rotated according to
the tire manufacturer’s recommended in-
tervals in the tire manufacturer’s warranty
pamphlet located in your vehicle literature
portfolio. If none is available, tires should
be rotated every 3 000 to 6 000 miles
(5 000 to 10 000 km), or sooner if neces-
sary, according to the degree of tire wear.
The same rotation (spinning) direction
must be maintained (
page 300).
Rotate tires before the characteristic tire
wear pattern becomes visible (shoulder
wear on front tires and tread center wear
on rear tires).
Thoroughly clean the mounting face of
wheels and brake disks, i.e. the inner side
of the wheels/tires, during each rotation.
Check for and ensure proper tire inflation
pressure.For information on wheel change, see the
“Practical hints” section (
page 369) and
(
page 388).
Warning!
G
Rotate front and rear wheels only if the tires
are of the same dimension.
If your vehicle is equipped with mixed-size
tires (different tire dimensions front vs.
rear), tire rotation is not possible.
Warning!
G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
80 lb-ft (110 Nm).
Only use genuine Mercedes-Benz wheel
bolts specified for your vehicle’s rims.